2.0 millimetres: Sram brings thick brake discs

A thicker brake disc has more mass for the same material. Therefore, more (braking) energy must be used to bring this mass to the same temperature as a brake disc with less mass. This is simple layman's physics. So it's clear that the new Sram HS2 rotor with a disc thickness of two millimetres (previously with Sram: 1.8 millimetres) should be less susceptible to brake fade under heavy braking. But the new disc has even more aces up its sleeve.

The technology: less fading, quieter brakes

A special, heat-dissipating coating on the black spokes should ensure better performance, the pads should also grip better thanks to a new profile and the disc should reduce noise when braking - previously a classic problem with many Sram disc brakes, especially in wet conditions. Overall, the manufacturer claims an increase in performance of seven per cent or, more specifically, a reduction in disc temperature of 40 degrees during continuous grinding braking (500 degrees with the HS2 disc, 540 degrees with the classic Centerline disc). We saw a similar picture in several disc brake tests on the BIKE test bench. Thicker discs were able to clearly set themselves apart in terms of heat resistance. The relatively thin discs from Sram and Shimano often surprised our test engineers. The new HS2 round discs from Sram therefore seem to be exactly the right step. As before, a rounded profile ensures easier wheel installation.

Weight versus performance: On which bikes does the new HS2 disc make sense?

Does the new disc also gain weight with the thickness? We have already tested two 6-hole test models with diameters of 200 and 220 millimetres. They weigh 205 and 260 grams without bolts. Only a few grams more than the previous disc (approx. 195 grams/200 mm). The choice is therefore easy, especially for heavy riders and on e-MTBs, fast enduro and downhill bikes. The thick round discs make perfect sense here. There will be a total of eight versions of the new HS2 disc: 160, 180, 200 and 220 millimetres each in 6-hole or centrelock versions. The prices are between 55 and 70 euros per disc.